Formulation of Different Chitosan Hydrogels for Cartilage Tissue Repair

Different formulations of Chitosan/sulphate and Chitosan/PEGDE were produced by physical and chemical reticulation to obtain hydrogels with better physiochemical properties. The hydrogels were analyzed – in terms of their non-toxicity, proliferative, differentiative, inflammatory and immunology responses. Commercial grade Chitosan (Sigma) was solubilized and purified by progressive filtrations. Then, the polymer was freeze-dried in a water soluble cationic form. A physical hydrogel was prepared by mixing a 3 % w/w water solution of the a.m. polymer with different stoichiometric ratios of (SO4=) 1/0.5;1/0.75;1/1 respectively. The hydrogels were cross-linked in multiwells. The chemical hydrog…

BIO-PULITURA: PROTEASI DA ORGANISMI MARINI.

Differential Expression of Proteolytic Enzymes During Epithelia-Mesenchyma Transcation of Endothelial Cells

Potential roles of extracellular vesicles in brain cell-to-cell communication

Potential roles of extracellular vesicles in brain cell-to-cell communication Extracellular vesicles (EVs) are released into thè extracellular space from both cancer and normal brain cells, and are probably able to modify thè phenotypic properties of receiving cells1. EVs released from astrocytes and neurons contain FGF2 and VEGF2'3 and induce a 'blood-brain barrier' (BBB) phenotype in cultured brain capillary endothelial cells (BCECs, unpublished results), On thè other hand, EVs from G26/24 oligodendroglioma induce apoptosis in neurons and astrocytes4-5. These effects are probably due to Fas Ligand and TRAIL, present in G26/24 vesicles4-5. Moreover, G26/24 EVs contain extracellular matrix …

PLLA Scaffold via TIPS for Bone Tissue Engineering

Tissue engineering offers a promising new approach to repair bone fractures, fractures that do not heal, and fractures due to bone tumors. In this work, two different approaches were tested in order to obtain Poly-L- Lactic Acid (PLLA) porous scaffolds via Thermally Induced Phase Separation (TIPS) for bone tissue engineering application. First, the possibility to produce a composite material, by incorporating Hydroxyapatite (HA) particles in a Poly-L-lactic acid (PLLA) matrix was investigated. Two PLLA/HA weight ratios (70/30 and 50/50) were tested. The results showed that the presence of HA does not influence the phase separation process, i.e. the composite scaffolds microstructure is simi…

Radiation engineered nanogels as platforms for medical diagnostics and therapeutic nanodevices

A scalable, single step, synthetic approach for the manufacture of biocompatible, functionalized microgels and nanogels has been developed. Pulsed EB irradiation of PVP aqueous solutions, at relatively low energies per pulse and doses within the sterilization dose range, has led to a variety of ‘as-born’ sterile, functional nanostructures that exhibit a combination of favourable properties which make them suitable as biomedical nanocarriers. Reactive functional groups have been generated by graft copolymerization of functional acrylic monomers. These groups can be used to attach fluorescent probes to the NPs, to bioconjugate ligands of specific cell receptors and to incorporate therapeutics…

CLUSTERING OF TYPE-II TRANSMEMBRANE SERINE PROTEASES (TTSPS) AND MATRIX METALLOPROTEINASES (MMPS) IN THE CELL SURFACE AND SHED MEMBRANE VESICLES OF ACTIVE ENDOTHELIAL CELLS.

Type-II transmembrane prolyl dipeptidases and matrix metalloproteinases in membrane vesicles of active endothelial cells.

Conclusions: Endothelia cells in sparse culture are migratory and increase the production of gelatinases of serine- and metallo-classes in membrane vesicles. Collectively, proteases associated with membrane vesicles degrade extracellular matrix components including type-I and type-IV collagens, laminin and fibronectin. Inhibitor studies suggest the existence of small gelatinases that were derived from these serine- and metallo-proteases. Thus, further studies are warranted to demonstrate the cooperative action of metallo- and serine proteases on cell surfaces and in extracellular vesicles during endothelial cell migration in 3D collagenous matrices, and potential proteolytic activation mech…

Proteolytic enzymes in membrane domains of endothelial cells cultured in type-1 collagen 3D gels

Novel protese from marine organisms with potential interest in restoration procedures

In the last decades molecular biology allowed the development of innovative protocols in the field of conservation/restoration of cultural assets. In this work we presents novel hydrolyses isolated from marine invertebrate organisms, whose protease activity was previously tested in laboratory by zymography on polyacrilamide gel (in presence of 0.1 of gelatin) Very interesting these enzymes are activated/work in a range of temperatures between 4 ° C and 37 ° C. In this study two sets of proteases were applied, to bio-clean works of art surfaces, at the environments temperature (19° to 25.5° C). Before remove, the water-soluble components of the layers have been analyzed by high-pressure size…

Vesicle mediated cell-cell and cell-matrix interactions

Graphene nanosystems as supports in siRNA Delivery

The nature of graphene-based nanosystems, as well as the possibility to synthesize them at low cost, have made them in the last few years, an interesting proposition in tumour therapy as a drug delivery system. Here, a reduced form of graphene oxide (RGO) has been synthesized and conjugated with a specific antibody for active targeting against tumour cells (RGOY). Furthermore, its bi-dimensional nature permits also p- p stacking interactions with planar molecules like siRNA (RGOY-siRNA). All these nano-complexes were characterized by DLS and DSC analysis, TEM and Raman spectroscopy and their biocompatibility was demonstrated by viability assay on cell line ECV 304. The system is able to be …

Hydroxyapatite/Chitosan/Collagen coatings through galvanic coupling

In this work, the attention was focused on Hydroxyapatite/ Chitosan/Collagen composite as biocoatings for application in orthopaedic devices. Hydroxyapatite was selected for its osteoconductivity due to its chemical structure similar to bones. Collagen has the same function since 90-95% of bone matrix is constituted of collagen fibers. Furthermore, chitosan are largely used yet in medical field (e.g. antibacterial agent or drug deliver) and in this work were used to create a synergic interaction with hydroxyapatite and collagen to increase the strength and bioactivity of coating. Coatings were fabricated by galvanic deposition process that has different advantages an it does not require ext…

Poly lactic acid based scaffolds for vascular tissue engineering

A critical obstacle encountered by tissue engineering is the inability to maintain large masses of living cells upon transfer from the in vitro culture conditions to host in vivo. Capillaries, and the vascular system, are required to supply essential nutrients, including oxygen, remove waste products and provide a biochemical communication "highway". The successful use of tissue-engineered constructs is currently limited to thin or avascular tissues, such as skin or cartilage, for which post-implantation neovascularisation from the host is sufficient to meet the demand for oxygen and nutrients. To succeed in the application of tissue engineering for bigger tissues, such as bone or muscle, t…

Clustering of type-II transmembrane serine proteases (TTSPs) and matrix metalloproteinases (MMPs) in the cell surface and shed membrane vesicles of active endothelial cells.

A new method to valued efficiency of enzyme blends for pancreas tissue digestion

One of the best successful examples of cell therapy is represented by islet transplantation since 1990. However islet isolation methods are not completely standardized yet. More than half of isolation procedures failed to isolate adequate islets for transplantation, due to variable pancreas conditions and to unpredictable enzymatic blend efficiency. Enzymes used for pancreas digestion include collagenases and neutral proteases: their composition and activity are largely variable between different batches. We set up a new in vitro method to better in vitro characterize enzymatic blend before its use in human pancreas. In our experimental approach human immortalized cells (ECV-304) or human is…

Glutathione-sensitive nanogels for drug release

Nanogels (NGs) synthesized by pulsed electron-beam irradiation of semi-dilute poly (N-vinyl pyrrolidone) (PVP) aqueous solutions, at relatively low energy per pulse and doses within the sterilization dose range, represent a very interesting family of polymeric nanocarriers. Ionizing irradiation-induced crosslinking of PVP allows to control particle size, and surface chemistry of the polymer nanoparticles without making use of catalysts, organic solvents or surfactants, and with beneficial effects onto the purity and hence biocompatibility of the final products obtained. Furthermore, the availability of reactive functional groups, either generated by the radiation or purposely grafted via co…